bundles/org.simantics.mapping/src/org/simantics/mapping/constraint/instructions/TripletPredicateQuery.java

   1 /*******************************************************************************\r
   2  * Copyright (c) 2007, 2010 Association for Decentralized Information Management\r
   3  * in Industry THTH ry.\r
   4  * All rights reserved. This program and the accompanying materials\r
   5  * are made available under the terms of the Eclipse Public License v1.0\r
   6  * which accompanies this distribution, and is available at\r
   7  * http://www.eclipse.org/legal/epl-v10.html\r
   8  *\r
   9  * Contributors:\r
  10  *     VTT Technical Research Centre of Finland - initial API and implementation\r
  11  *******************************************************************************/\r
  12 package org.simantics.mapping.constraint.instructions;\r
  13 \r
  14 import gnu.trove.set.hash.TIntHashSet;\r
  15 \r
  16 import java.util.ArrayList;\r
  17 import java.util.Collection;\r
  18 import java.util.Iterator;\r
  19 \r
  20 import org.simantics.db.ReadGraph;\r
  21 import org.simantics.db.Resource;\r
  22 import org.simantics.db.Statement;\r
  23 import org.simantics.db.exception.DatabaseException;\r
  24 import org.simantics.layer0.Layer0;\r
  25 \r
  26 public class TripletPredicateQuery extends TripletInstruction {\r
  27 \r
  28         Resource predicate;\r
  29         \r
  30         public TripletPredicateQuery(int variable0, int variable1, int variable2,\r
  31                         Resource predicate) {\r
  32                 super(variable0, variable1, variable2);\r
  33                 this.predicate = predicate;\r
  34         }\r
  35         \r
  36         public TripletPredicateQuery(int variable0, int variable1, int variable2) {\r
  37                 super(variable0, variable1, variable2); \r
  38         }\r
  39         \r
  40         @Override\r
  41         public Object query(ReadGraph g, Object[] bindings) throws DatabaseException {\r
  42                 Resource r0 = (Resource)bindings[variable0];\r
  43                 Resource r2 = (Resource)bindings[variable2];\r
  44                 Collection<Resource> result = new ArrayList<Resource>();\r
  45                 for(Statement stat : \r
  46                         predicate == null ? \r
  47                                 g.getStatements(r0, Layer0.getInstance(g).IsWeaklyRelatedTo) : \r
  48                                 g.getStatements(r0, predicate))\r
  49                         if(stat.getObject().equals(r2))\r
  50                                 result.add(stat.getPredicate());\r
  51                 if(result.isEmpty())\r
  52                         return IInstruction.FAILURE;\r
  53                 Iterator<Resource> it = result.iterator();\r
  54                 bindings[variable1] = it.next();\r
  55                 if(it.hasNext())\r
  56                         return it;\r
  57                 else\r
  58                         return null;\r
  59         }\r
  60         \r
  61         @SuppressWarnings("unchecked")\r
  62         @Override\r
  63         public Object next(ReadGraph g, Object[] bindings, Object continuation) {\r
  64                 Iterator<Resource> it = (Iterator<Resource>)continuation;\r
  65                 if(it.hasNext()) {\r
  66                         bindings[variable1] = it.next();\r
  67                         if(it.hasNext())\r
  68                                 return it;\r
  69                         else\r
  70                                 return null;\r
  71                 }\r
  72                 else\r
  73                         return IInstruction.FAILURE;\r
  74         }       \r
  75         \r
  76         @Override\r
  77         public void collectVariables(TIntHashSet reads, TIntHashSet writes) {           \r
  78                 super.collectVariables(reads, writes);\r
  79                 writes.add(variable1);\r
  80         }\r
  81 \r
  82 }\r